This patch adds all the language-level function keywords defined in:
https://github.com/ARM-software/acle/pull/188 (merged) https://github.com/ARM-software/acle/pull/261 (update after D148700 landed)
The keywords are used to control PSTATE.ZA and PSTATE.SM, which are
respectively used for enabling the use of the ZA matrix array and Streaming
mode. This information needs to be available on call sites, since the use
of ZA or streaming mode may have to be enabled or disabled around the
call-site (depending on the IR attributes set on the caller and the
callee). For calls to functions from a function pointer, there is no IR
declaration available, so the IR attributes must be added explicitly to the
call-site.
With the exception of 'arm_locally_streaming' and 'arm_new_za' the
information is part of the function's interface, not just the function
definition, and thus needs to be propagated through the
FunctionProtoType::ExtProtoInfo.
This patch adds the defintions of these keywords, as well as codegen and
semantic analysis to ensure conversions between function pointers are valid
and that no conflicting keywords are set. For example, 'arm_streaming'
and 'arm_streaming_compatible' are mutually exclusive.
Also, would it be better to use a bitmask enumeration here? https://github.com/llvm/llvm-project/blob/main/llvm/include/llvm/ADT/BitmaskEnum.h